Furnace



(No Model.)

J. CAMPBELL.

ROASTING FURNAGB.

Patented Nov. 1,1881,

FIE-LI.-

INVENTEIR: I 0%, (E A/bud WITNESSES UNITED STATES PATENT OFFICE,

AND MESNE ASSIGNMENTS, PANY, OF NEW YORK, N. Y.

TO THE CAMPBELL DESULPHURIZING COM- ROASTING=FURNACE.

SPECIFICATION forming part of Letters Patent No. 248,912, dated November 1, 1881.

Application flied August 11, 1880.

To all whom it may concern Be it known that I,JOHN CAMPBELL, of Allegheny city, Allegheny county, Pennsylvania, have invented certainnewanduseful Improvements in Roasting-Furnaces, of which the following is a specification.

My invention has relation to those furnaces for roasting ordesulphurizing ores, or for renovating bone-black, or for similar purposes, in

which the granulated ore or other material is showered into an upright shaft having zigzag inclined sides, through which flame passes to purify the falling material by burning out the consumableimpurity therefrom; and myinvention aims to provide a furnace acting on this principle by which the material will be more effectually exposed to the action of the flame. To this end the leading feature of my invention may be stated to consist in an upright shaft having its internal passage formed with a zigzag series of inclines in the form of cones placed alternately base to base and apex to apex, whereby the passage becomes of annular conical form, alternately converging and diverging, so that the showerof ore falls in azigzag contracting and diverging course through and across the ascending flame, and thereby effects a more perfect exposure of the material to the flame, and produces an energetic sift- 0 ing or agitation thereof in falling into and being reflected from the succeeding cones,which causes the more complete consumption and removal of the impurities from the falling matter, and is hence a material improvement over 5 the simple zigzag passages heretofore employed without conical contraction or enlargement.

Figure 1 of the drawings annexed gives a vertical section of my improved furnace, and

Fig. 2 a cross-section thereof on line mm.

In the drawings, a indicates the shaft of the furnace, which rises from a suitable foundation to a height which is determined by the requirements of the material to be treated.

5 Near the base of the shaft a large gas-burner, b, emits a column of flame upward through the shaft, and at the top of the shaft a hopper, c, delivers the granulated or pulverized ore or other material to be purified centrally into the (No model.)

top of the shaft, which, falling through the flame, becomes purified and is received into the receptacle d in the base of the furnace below the gas-burner, from which receptacle the purified material is removed when accumulated. As may be now observed, the passage through the shaft is not direct, but presents a series of zigzag conical inclines to the falling ore and ascending flame. This zigzag passageis of annular and conical form,and is preferably produced by constructing the interior of the shaft with a series of conical contractions and enlargements, like a series of concave truncated cones placed base to base and apex to apex, and also in arranging centrally within the same a corresponding series of convex cones, e e, of smaller diameter, leaving an annular zigzag conical space between the two,

as will be readily understood from the drawings. The shaft (0 is constructed either of iron of orfire-brick boundwithi.ron,and the central series of cones c is preferably formed of castiron, each double cone of the series being cast hollow and secured to a tubular rod, f, which extends from a cross-tube,g, fixed transversely in the top of the shaft, and by which the central series of cones is thus suspended in the shaft.

The chute h of the feeding-hopper 0 discharges centrally in the shaft, over the tip of the inner series of cones, and the gas burner Z) impinges its flame against the tip of the lowermost cone, which is thence spread out and rises in an alternatingcontractingand expanding column or sheet through the zigzag passage of the shaft.

The granulated or powdered ore, bone-black, or other material to be purified is fed into the hopper c, and is thence discharged from the chute h in an annular stream over the upper convex cone, and thence descends inadiverg- 9o ing shower across the flam e-passage, and, striking the first incline in the shaft, a portion be comes reflected thereby and falls through the flame, and a portion slides down the incline, and these portions, again converging, strike 5 the next of the inner cones, and the descending material thence continues in its zigzag pas sage in an alternately converging and diverging shower, alternately passing across and through the flame till it finally falls in a purified condition into the receptacle (1 at the bottom of the shaft.

It may be observed that by the means described the falling material is most thoroughly exposed to the flame, for, owing to its zigzag passage and its falling alternately from and onto opposite inclines, its descent becomes momentarily retarded, and it is thus kept longer in the flame, and all sides of the particles are presented in different directions to the flame, while the alternate impact of the particles on the successive inclines and their alternate divergence and con vergcn cc produces such a friction between the particles and such an agitating or sifting action as tends efl'ectuallyto further break up the particles and rub off and remove the lighter adhering impurities which become thrown as fine dust into the flame, by which it is immediatelyconsumed, thereby producing such an energetic action as will remove all perceptible trace of sulphur or arsenic t'rom ores, or other consumable or volatile impurities, from whatever material may be treated.

I prefer to admit an air-blast through the crosspipes g and central pipe, f, into the central cones, from which it is discharged in jets near the lower apex of each double cone into the passage of the shaft, to increase the intensity of the flame therein at certain points, and the air so admitted will also serve to keep the cones from being too highly heated.

The gas-burner b is preferably of a compound character now largely employed, being supplied with jets of gas, steam, and air, as may be inferred, from the three pipes connecting therewith; but any suitable gas-burner or other source of flame may be employed, a gasflame being, however, manifestly superior for the purposes described.

What I claim as my invention is- A roasting-furnace having a shaft formed with a series ofconical concave contractions and enlargements, and a central corresponding series of convex cones of smaller diameter, leaving an annular conical and zigzag passage between the two, substantially as and for the purpose set forth.

JOHN CAMPBELL.

VVituesses:

CHAS. M. HIGGINS, J NO. E. GAVIN. 

